Turning Machinability of SiC Particle Reinforced Aluminum Alloy Composites

The machining of SiC particle-reinforced aluminum alloy composites was performed using a lathe and PCD tools, and the effects of the particle size and the volume fraction of the SiC particles on the machinability was discussed. Composites were fabricated by squeeze casting. The range of the cutting force fluctuations during the cutting of the alloy became slightly narrower due to the reinforcement, while the average values increased due to the reinforcement. The resistance with larger volume fractions was higher. When comparing the composites with different SiC particle sizes within the same volume fraction, there was minimal variation in the resistance. The reinforcement decreased the surface roughness, achieving a finish closer to the theoretical surface roughness, indicating that the reinforcement reduces the formation of the built-up edge during the cutting. The roughness of the composites with 4 μm particles was lower than that of the composites with 25 μm particles. The flank wear of the tool after machining the composite with the 25 μm particles was more severe than that after machining the composites with the 4 μm particles. Larger particles in the composite would promote stress concentration leading to local fractures then the formation of partially agglomerated areas of the pulverized particles on the machined surface. Conversely, smaller particles would distribute the stress more evenly throughout the matrix, thus reducing the stress concentration. This would lead to a smoother surface and decrease in the tool wear.